Composite treatment process of inorganic powder and composite powder

Abstract

The invention relates to the field of inorganic powder preparation, and particularly discloses a composite treatment process of inorganic powder and composite powder. Firstly, slurry of active hydrated silica is prepared through reaction of sodium silicate and aluminum sulfate, then powder to be subjected to composite adhesion is prepared into powder slurry, the powder slurry and active slurry are mixed, filter pressing, washing and gradient drying are conducted to achieve adhesion of the powder, and finally surface treatment is conducted through silane and an antibacterial agent. The composite process is simple, the powder is high in adhesion, heat resistance, weather resistance and antibacterial property, and the application range and the service life of the composite powder are widened.

Description

Technical Field

[0001] This application relates to the field of inorganic powder preparation, and more specifically, it relates to a composite processing technology for inorganic powders and composite powders. Background Technology

[0002] Inorganic composites have always been a key research area in materials science. Adhesion, grafting, and loading between powders can increase surface area and improve dispersion. The bonding of different powders can endow them with various properties. For example, titanium dioxide loaded on mica can improve its dispersion and enhance its antibacterial, UV-protective, and anti-aging properties; zinc oxide loaded on mica in cosmetics can improve sun protection and oil absorption effects; and silica loaded on calcium carbonate, as an adsorbent material, can improve adsorption efficiency in environmental remediation applications.

[0003] Current market methods often involve high-speed dispersion and mixing on mixing equipment to obtain highly uniform powders. However, these powders exhibit poor adhesion and stability. Some special types of powders, due to their inherent active groups, can be chemically precipitated on certain powder surfaces through chemical reactions to achieve powder composites. However, these methods are often not universally applicable, and the precipitated substances after such treatment are often inconsistent with the original substances, thus limiting their application. Furthermore, chemical precipitation involves various organic bridging agents, resulting in high costs. Therefore, a simple and universal powder composite method is needed.

[0004] Composite powders have a wide range of applications, including environmental self-repair (such as wastewater treatment), gas adsorption, increasing the strength and anti-aging properties of various materials, and as additives in daily cosmetics. In these applications, powders often need to possess high weather resistance, heat resistance, and antibacterial properties to meet the requirements of different scenarios and long-term use. Imparting certain properties to powders during the composite process is one solution, but current powders still do not fully meet the requirements in terms of heat resistance, weather resistance, and antibacterial properties, enabling them to be used effectively for extended periods under various harsh conditions.

[0005] In summary, it is necessary to develop a composite powder that has a simple compounding process, strong applicability, and is weather-resistant and antibacterial. Summary of the Invention

[0006] To simplify the powder composite processing technology, improve the overall performance of inorganic composite powders, and enhance the long-lasting effectiveness of powders, this application provides a composite processing technology for inorganic powders and a composite powder.

[0007] In a first aspect, this application provides a composite processing technology for inorganic powders, characterized in that the composite processing technology includes: Step 1: Dissolve sodium silicate in deionized water at a constant temperature of 60-90℃ by stirring to obtain a sodium silicate solution; dissolve aluminum sulfate in deionized water at a constant temperature of 60-90℃ by stirring to obtain an aluminum sulfate solution; slowly add the aluminum sulfate solution to the sodium silicate solution and stir until the solution becomes a milky white slurry, and continue stirring for 10-20 minutes to obtain an active slurry; Step 2: Add the powder to the reactor, then add an ethanol aqueous solution and stir to form a slurry. The reactor temperature is 60-90℃. Step 3: Add the active slurry from Step 1 to the slurry from Step 2 and stir for 30-50 minutes to obtain a mixed slurry.

[0008] Step 4: Press the mixed slurry, wash it with water, dry it at 80-90℃, and then heat it to 105-120℃ to dry it again to obtain filter cake; Step 5: The filter cake is fed into a high-speed mixer, silane is added, the mixture is mixed, dried again, and crushed into composite powder by a hammer mill.

[0009] This process provides a general method for powder composite processing. Compared with organic chemical bridging, physical mixing or deposition, and in-situ reactions, the process of this application does not require organic bridging agents, uses environmentally friendly raw materials, has simple process steps, and produces powders with high adhesion, thus providing more application scenarios for composite powders.

[0010] This application first prepares a slurry of active hydrated silica through the reaction of sodium silicate and aluminum sulfate. Then, the powder to be composite-adhesive is prepared into a powder slurry and mixed with the active slurry. The mixture is then filtered, washed, and dried to achieve better powder adhesion. The inventors believe this is likely because the slurry from the reaction of sodium silicate and aluminum sulfate contains active hydrated silica. When heated, the hydrated silica loses water to become SiO2. Freshly dehydrated SiO2 has highly reactive silicon-oxygen bonds, which can react with the hydroxyl groups on the powder surface, binding them together to achieve adhesion and loading between powder particles. The powder particles are bonded by silicon-oxygen bonds, resulting in high adhesion strength. Compared to organic bridging agents such as silane coupling agents, it exhibits better adhesion and tighter bonding. The hydrated silica generated in the reaction is directly mixed with the powder in slurry form, expanding the contact area and significantly increasing the adhesion sites. After filtration and dehydration, the active silica loses water to complete adhesion, thus achieving better powder bonding.

[0011] Specifically: In step 1, sodium silicate is added to 10 times its own weight of deionized water to form a sodium silicate solution; aluminum sulfate is added to 5 times its own weight of deionized water to form an aluminum sulfate solution; the aluminum sulfate solution is slowly added to the sodium silicate solution and stirred at a speed of 1000-1500 rpm. In step 2, the powder is added to the reactor, along with a 5% ethanol aqueous solution with a mass concentration of 10-20 times the weight of the powder. In step 3, the stirring speed is 1500-2000 rpm; more preferably 1800 rpm. In step 4, the mixed slurry is filtered by pressure and washed with water until the conductivity is ≤150μS / cm. The water washing is then stopped to remove water-soluble salts. The slurry is then sent to a hot air circulating oven for drying. The drying temperature is set at 80-90℃ for 10-14 hours. The temperature is then increased to 105-120℃ and the drying continues for 18-24 hours. In step 5, the obtained dried filter cake is put into a high-speed mixer, and the mixing speed is set to 1000-1500 rpm. The filter cake is broken into powder again and forms a vortex under the action of the high-speed mixer. Silane is added to it and the mixture is mixed for 10-30 minutes. The mixed powder is then placed in a hot air circulating oven for drying again. The drying temperature is set to 100-120℃ and the powder is dried for 8-10 hours to allow the silane and powder to combine smoothly. The mixed powder is taken out of the oven and further crushed using a hammer mill to obtain the finished composite powder.

[0012] By adjusting the solution preparation and stirring speed, sodium silicate and aluminum sulfate can achieve a better contact reaction. The drying and dehydration process in step 4 is an important step for powder adhesion. By first drying at a temperature of 80-90℃ for 10-14 hours, and then increasing the temperature to 105-120℃ and continuing to dry for 18-24 hours, gradient drying can effectively control the dehydration process. Adjusting the dehydration time can achieve gradual dehydration to fully utilize the bonding activity of the silicon-oxygen bonds of the newly dehydrated SiO2, thus achieving better adhesion.

[0013] In some implementations, the molar ratio of sodium silicate and aluminum sulfate is adjusted based on the reaction equation. The molar ratio can be set according to the equation, or sodium silicate can be slightly in excess, such as a molar ratio of (3.1-3.3):1. Adjusting to an excess of sodium silicate promotes powder adhesion. Besides participating in the reaction, sodium silicate also regulates the entire reaction under weakly alkaline conditions. This not only increases the reaction rate but also results in lower particle density of the hydrated silica formed under weakly alkaline conditions, which is beneficial for dispersion and provides more adhesion sites during the subsequent dehydration process, thus achieving better adhesion between powder particles.

[0014] In some embodiments, the powder in step 2 is the main raw material component 1, which contains at least one of the following: synthetic fluorophlogopite, mica, sericite, talc, silica, sodium calcium aluminum silicate, titanium dioxide, iron oxide, pearl powder, calcium carbonate, boron nitride, zinc oxide, aluminum hydroxide, aluminum oxide, lauroyl lysine, and ceramide NP.

[0015] The composite process described in this application is versatile and applicable to the adhesion of various powders, thereby expanding the application fields based on composite powders. For example, calcium carbonate loaded with porous silica as an adsorbent can increase the adsorption area, thereby achieving more efficient wastewater treatment and benefiting environmental remediation; iron oxide loaded on mica can enhance the coloring effect of iron oxide on the substrate based on the effect of mica, achieving a more stable and uniform color; nano-titanium dioxide loaded on mica can further improve its antibacterial, anti-UV aging and anti-aging effects; the rough structure of the powder structure composed of silica and talc can act as a matting agent to improve the matting effect of the substrate; zinc oxide loaded with mica, when applied to cosmetic powders, can provide excellent sun protection, adhesion, and oil absorption. In some embodiments, the powders can be the same or different powders, achieving composites between various powders based on different needs.

[0016] In some embodiments, the silane in step 5 is raw material component 2, which includes at least one of triethoxyoctylsilane, polydimethylsiloxane, etc.

[0017] In some embodiments, the mass ratio of powder to silane is 100:(1-10); it is understood that when 100 parts of powder are added, the amount of silane added can be 1-10 parts.

[0018] The lifespan of composite powders varies depending on the application environment. For example, powder failure caused by high-temperature and high-humidity operations, or erosion due to insufficient antibacterial properties in environmental remediation projects such as water purification, all affect the use of composite powders and limit their application range. Therefore, improving the performance of powders in the compounding process to extend their application range and service life is an important issue. Heat resistance, weather resistance, and antibacterial properties are key factors affecting the lifespan of composite powders. Therefore, the inventors chose silanes for surface treatment in the composite modification of powders. It should be understood that, based on various conventions for expressing silicon compounds, silanes here are not limited to silane coupling agents, but include silane coupling agents and polysiloxane compounds.

[0019] Inorganic powders can be treated with silanes to improve their oil solubility to a certain extent. Triethoxyoctylsilane and polydimethylsiloxane are both common silane choices that can achieve oil treatment of inorganic powders. By controlling the mass ratio of powder to silane, the powder's own properties can be fully utilized while ensuring that it has the required oil solubility.

[0020] Understandably, silanes have excellent interfacial compatibility and coupling properties, which are beneficial for surface modification. They also have excellent thermal stability, water resistance, chemical corrosion resistance, and weather resistance. Therefore, through the composite modification of silanes, the limitations of composite powders in harsh environments can be effectively overcome, the application fields of powders can be broadened, and the service life of powders can be extended.

[0021] In some embodiments, an antibacterial agent is added simultaneously with the silane in step 5; the antibacterial agent is a polysiloxane-b-sulfonic acid carboxylic acid complexed silver segment and a styrene-b-quaternary ammonium salt segment-b-long-chain hydrophobic polyolefin copolymer. In some embodiments, the mass ratio of silane to antibacterial agent is 8:(2-4).

[0022] Even with unique advantages in heat and weather resistance, silanes do not offer satisfactory antibacterial properties, particularly long-lasting antibacterial activity. Considering the long-term effectiveness of composite powders, sustained and highly effective antibacterial properties are essential. Therefore, modifying silanes by adding antibacterial agents can improve the heat resistance, weather resistance, and antibacterial properties of composite powders, thereby maintaining long-term effectiveness and extending service life.

[0023] Antimicrobial agents include silver-based antimicrobial agents, ammonium salt antimicrobial agents, microbial antimicrobial agents, biguanide antimicrobial agents, etc. The main requirements for antimicrobial agent applications are to improve antimicrobial efficiency and long-lasting antimicrobial activity. Combining different antimicrobial agents can enhance antimicrobial properties, but inventors need to consider how to achieve even more efficient combinations to further meet antimicrobial requirements. Furthermore, while sustained-release antimicrobial technology achieves long-lasting antimicrobial activity to some extent, the loss of antimicrobial ions can lead to insufficient antimicrobial efficiency after a long period, and the need to prepare and utilize various sustained-release carriers also increases application costs.

[0024] In seeking to address the problem of providing high antibacterial rate and long-lasting antibacterial properties in composite powders, the inventors unexpectedly and effectively improved the antibacterial rate and maintained its high efficiency for a long time by using a combination of polysiloxane-b-sulfonic acid carboxylic acid complexed silver segments and styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin copolymers for antibacterial purposes. This is likely because, by complexing silver with organic acids and then modifying the polysiloxane segments, the silver particles are less prone to agglomeration and precipitation, allowing for stable distribution. Furthermore, the similar or identical segments of the polysiloxane and silane can promote the dispersion of metallic silver within the silane, further preventing agglomeration. Through these two mechanisms, the final metallic silver is uniformly and stably dispersed on the powder surface, resulting in multiple uniform antibacterial sites that can exert a stable and continuous effect. For styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin copolymers, the quaternary ammonium salt provides certain antibacterial properties, the phenyl group of the aromatic ring can form π-π stacking with the aromatic amino acids in the bacterial membrane, thereby improving the adsorption of bacteria, and the long-chain alkane of the hydrophobic long-chain segment can insert into the lipid layer of the bacterial membrane, disrupting the bacterial membrane. Therefore, this triblock polymer adsorbs bacteria through the action of the benzene ring block, the hydrophobic long-chain segment on the side disrupts the bacterial membrane, and the quaternary ammonium salt in the middle segment further disrupts the cell membrane and inhibits enzyme activity by electrostatic adsorption on the bacterial surface. The three components form a synergistic bactericidal effect based on the block structure, effectively improving the bactericidal activity.

[0025] The inventors further discovered that when polysiloxane-b-sulfonic acid carboxylic acid complexed silver and styrene-b-quaternary ammonium salt segment-b-long-chain hydrophobic polyolefin copolymer are used together, a significant improvement in unexpected and long-lasting antibacterial effects is achieved. This is because, on the one hand, the polysiloxane-b-sulfonic acid carboxylic acid complexed silver and the styrene-b-quaternary ammonium salt segment-b-long-chain hydrophobic polyolefin copolymer achieve synergistic bactericidal effects based on the aforementioned different antibacterial mechanisms. On the other hand, when the two are mixed as a bactericide, the silver in the polysiloxane-b-sulfonic acid carboxylic acid complexed silver is mainly distributed in the sulfonic acid carboxylic acid segment, while the polymer monomer in the intermediate segment of the styrene-b-quaternary ammonium salt segment-b-long-chain hydrophobic polyolefin includes acryloyloxyethyltrimethylammonium chloride. The hydrogen bonding between the acrylic acid and secondary amine groups in the acrylic acid complexed silver and the silver drives the aggregation of the two bactericidal groups. The intermediate chain segment forms a benzene ring that adsorbs bacteria, while the hydrophobic long chain disrupts the cell wall. The synergistic bactericidal structure of the intermediate chain segment quaternary ammonium salt and silver particles enhances their bactericidal effect. Furthermore, the polysiloxane in the polysiloxane-b-sulfonic acid carboxylic acid complex silver also promotes the dispersion of the styrene-b-quaternary ammonium salt segment-b-long-chain hydrophobic polyolefin copolymer in the silane, forming a highly bactericidal molecular structure with polydispersity, multiple sites, and different group combinations on the powder surface. The two bactericidal components complement each other based on their structure and bonding, resulting in a synergistic enhancement of the antibacterial effect. In addition, the hydrogen bonding between the two bactericidal components weakly coats the antibacterial silver, slowing down the silver loss rate and further ensuring the long-term stability of the metallic silver, preventing aggregation, releasing silver ions, and improving the long-lasting antibacterial effect.

[0026] In some embodiments, the mass ratio of polysiloxane-b-sulfonic acid carboxylic acid complexed silver segments to styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin copolymer is 4-6:1.

[0027] Based on the antibacterial properties of polysiloxane-b-sulfonic acid carboxylic acid complexed silver segments and styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin copolymers, adjusting their ratio ensures a better synergistic bactericidal effect. Too little styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin copolymer weakens the synergistic effect between the polysiloxane-b-sulfonic acid carboxylic acid complexed silver segments and the terpolymer, reducing the weak coating effect of the antibacterial silver, both of which are detrimental to efficient and long-lasting antibacterial activity. Conversely, too little polysiloxane-b-sulfonic acid carboxylic acid complexed silver segments results in less silver ion release, poorer dispersion of the antibacterial agent within the silane, and a decrease in overall antibacterial efficacy. Therefore, experiments have shown that maintaining the above-mentioned ratio achieves a superior antibacterial rate and more durable, highly efficient antibacterial effect.

[0028] In some embodiments, the preparation process of the polysiloxane-b-sulfonic acid carboxylic acid complex silver segment includes: brominizing an aminopolysiloxane to obtain a macromolecular initiator, then initiating the polymerization of 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid through the macromolecular initiator to obtain a copolymer, immersing the copolymer in a silver ion solution, and reducing it in situ with a reducing agent to obtain the product.

[0029] Specifically, it includes the following steps: Step 11: Add 10-20 parts of amino-terminated polysiloxane to 300 parts of solvent and stir to disperse for 10-14 min. Add 0.4-0.6 parts of triethylamine under an ice-water bath, then add 1.1-1.2 parts of 2-bromoisobutyryl bromide and stir to react for 0.9-1.2 h. Then react at 25°C for 18-22 h, remove the mixed solvent to obtain the macromolecular initiator. Step 12: 20 parts of 2-acrylamide-2-methylpropanesulfonic acid and 80 parts of acrylic acid are added to 400 parts of mixed solvent. Nitrogen gas is introduced, and 80-120 parts of the macromolecular initiator obtained in step 11, 3-4 parts of catalyst, and 6-8 parts of ligand are added. The temperature is raised to 85-88℃ and reacted for 6-8 hours. After the reaction is completed, the solvent is removed to obtain the copolymer. Step 13: Add the copolymer obtained in step 12 to 900-1100 mL of 0.1 mol / L silver nitrate solution, heat to 30-38℃ and stir for 10-12 min, then add 200-300 mL of 0.1 mol / L sodium borohydride solution and continue stirring for 1-2 h. After completion, separate the solvent and dry to obtain polysiloxane-b-sulfonic acid carboxylic acid complex silver segments.

[0030] Any good solvent suitable for the reaction in step 11 can be selected as the solvent, such as toluene, DMF, or cyclohexane; in one embodiment, the solvent in step 11 is toluene. Step 12 involves a conventional atom transfer radical polymerization system, including ATRP and AGET-ATRP synthesis processes, which can be used to prepare copolymers with regular structures, controllable molecular weights, and narrow molecular weight distributions. In some embodiments, the catalyst in step 12 is cuprous bromide (CuBr), and the ligand is pentamethyldiethylenetriamine. Similarly, any good solvent suitable for the polymerization reaction in step 12 can be selected, such as DMF, toluene, acetone, and isopropanol. In some embodiments, the mixed solvent can be a mixture of acetone and toluene in a volume ratio of 4:1.

[0031] This application preferably utilizes the above-mentioned process, employing a mature two-step polymerization process of bromination and ATRP, with well-defined reaction conditions, high yield, and simple process. The ATRP polymerization method allows for control of molecular weight through reaction time, resulting in molecular chain segments of appropriate length. It is understood that excessively long acid-containing segments hinder polymer dispersion in silanes, while excessively short acid-containing segments limit the amount of silver complexed, both of which impede the efficient exertion of antibacterial properties.

[0032] The co-polymerization of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid monomers as chain segments is more conducive to improving antibacterial effects. The acid-containing chain segments can complex silver ions, enabling in-situ reduction based on adsorption, complexation, and steric hindrance to generate metallic silver in situ, which is less prone to aggregation. The introduction of 2-acrylamido-2-methylpropanesulfonic acid into the polymer provides better steric hindrance, improving the dispersion of generated silver. Furthermore, the secondary amine in acrylamide-2-methylpropanesulfonic acid enhances the weak coating of the generated silver, while the carboxylic acid can improve the complexation stability of metallic silver through coordination with polycarboxylic acids. The combined use of both not only effectively inhibits the aggregation of generated silver particles but also better synergizes with styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin copolymers, enhancing the long-lasting and highly effective antibacterial effect. Understandably, the amount of 2-acrylamide-2-methylpropanesulfonic acid used, based on the total amount of monomers, is preferably less than 50%, more preferably 20%; an appropriate amount of 2-acrylamide-2-methylpropanesulfonic acid enhances the high efficiency and long-lasting antibacterial properties of silver while maintaining the high efficiency antibacterial properties of the quaternary ammonium salt.

[0033] In some embodiments, the preparation process of the styrene-b-quaternary ammonium salt segment-b-long chain hydrophobic polyolefin copolymer includes the following steps: the polymerization of monomers styrene, acryloyloxyethyltrimethylammonium chloride and dodecyl vinyl ether monomers is initiated stepwise by an ATRP initiator to obtain a terpolymer.

[0034] Specifically, it includes the following steps: Step 21: Add 50 parts of styrene to 300 parts of toluene, purge with nitrogen, add 0.5 parts of initiator, 3-4 parts of catalyst, and 6-8 parts of ligand, heat to 85-95℃ and react for 6-8 hours. After the reaction is complete, remove the solvent and dry to obtain polymer A. Step 22: Add 50 parts of acryloyloxyethyltrimethylammonium chloride to 500 parts of mixed solvent, purge with nitrogen, add polymer A obtained in step 11, 3-4 parts of catalyst, 6-8 parts of ligand, heat to 85-95℃ and react for 6-8 hours. After the reaction is completed, remove the solvent and dry to obtain polymer B. Step 23: Add 50 parts of dodecyl vinyl ether to 800 parts of mixed solvent, purge with nitrogen, add polymer B obtained in step 22, 3-4 parts of catalyst, 6-8 parts of ligand, heat to 90-100℃ and react for 6-8 hours. After the reaction is complete, remove the solvent and dry to obtain styrene-b-quaternary ammonium salt segment-b-long chain hydrophobic polyolefin copolymer.

[0035] ATRP polymerization is a conventional process for polymerizing terpolymers. ATRP polymerization produces chain segments with uniform length and site distribution, which is more conducive to the distribution of antibacterial sites on the surface. In the molecular structure of styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin copolymer, styrene segments and long-chain hydrophobic polyolefin copolymers are grafted on both sides of the quaternary ammonium salt segment. The side chains of the monomer acryloyloxyethyltrimethylammonium chloride unit contain quaternary ammonium salt and ester groups. Therefore, the side chains of the formed segments also contain multiple ester groups and quaternary ammonium salts. Combined with the groups in the sulfonic acid carboxylic acid complex silver segments and the hydroxyl groups on the surface of the composite powder, the segments can better adhere to the powder surface, improving the antibacterial stability of the powder surface. When the more free segments on both sides come into contact with bacteria, they can better exert the synergistic bactericidal effect of the phenyl groups and hydrophobic long chains on both sides, and facilitate the adsorption of bacteria to the powder surface with bactericidal groups, thus achieving a synergistic bactericidal effect. Experiments have also shown that this ternary structure has some improvement in bactericidal effect compared to ternary structures with adjacent phenyl segments and hydrophobic long chain segments.

[0036] On the other hand, this application provides a composite powder prepared by the above-described composite processing technology for inorganic powders. It is understood that this powder, obtained through the above process, can achieve all the beneficial effects imparted to the powder by the process.

[0037] In summary, this application has at least the following beneficial effects: 1. This application prepares composite powder by contacting sodium silicate and aluminum sulfate reactive slurry and composite powder slurry, combined with specific reactant molar ratio adjustment and gradient temperature drying process to achieve powder adhesion between powders, providing a simple process with few raw materials and wide applicability.

[0038] 2. This application improves the high temperature resistance, weather resistance, and antibacterial properties of the powder by incorporating silane and antibacterial agents into the composite powder process, thereby enhancing the long-term effectiveness of the powder, endowing it with more properties, and broadening the application field of composite powder. By using polysiloxane-b-sulfonic acid carboxylic acid complex silver segments and styrene-b-quaternary ammonium salt segments-b-long-chain hydrophobic polyolefin copolymer in a specific ratio as antibacterial agents, the antibacterial rate and long-lasting antibacterial effect of the antibacterial agent are unexpectedly and significantly improved.

[0039] 3. This application improves antibacterial properties by co-polymerizing sulfonic acid and carboxylic acid in polysiloxane-b-sulfonic acid carboxylic acid segments and in-situ complexing silver. By selecting monomers and designing segments of styrene-b-quaternary ammonium salt-b-long-chain hydrophobic polyolefin terpolymers, the antibacterial properties of the powder are optimized and improved after the antibacterial agent participates in the powder composite modification. Attached Figure Description

[0040] Figure 1 This is a SEM image of nano-zinc oxide adhered to mica powder in Example 1 of this application; Figure 2 This is a SEM image of the synthesized mica self-adhesive powder from Example 2 of this application; Detailed Implementation

[0041] To further aid in understanding the technical solution of the present invention, several specific embodiments are provided to describe the technical solution of the present invention in more detail. All described embodiments are only some embodiments of the present invention, not all of them; embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The following embodiments are further illustrations of the present invention, but the present invention is not limited thereto.

[0042] The raw materials used in the embodiments and preparation examples of this application are all conventional commercially available brands, or can be obtained according to conventional processes. Among them, the polydimethylsiloxane is Dow Corning PMX-200 350cs; the amino-terminated polysiloxane is WACKER® FLUID NH30D; the nano zinc oxide is purchased from Qingdao Jinna New Materials, with a particle size of 30 nanometers; the mica is purchased from Anhui Henghao Technology, with a particle size of 10-14 micrometers; and the synthetic mica is purchased from Guangxi Qise Pearl Materials, with a particle size of 10-15 micrometers. Example

[0043] Preparation Example 1 Preparation of polysiloxane-b-sulfonic acid carboxylic acid complex silver segments Step 11: Add 15 parts of amino-terminated polysiloxane to 300 parts of toluene and stir to disperse for 12 min. Add 0.5 parts of triethylamine under an ice-water bath, and then add 1.15 parts of 2-bromoisobutyryl bromide and stir to react for 1 h. Then react at 25 °C for 20 h, and remove the solvent to obtain the macromolecular initiator. Step 12: 20 parts of 2-acrylamide-2-methylpropanesulfonic acid and 80 parts of acrylic acid are added to 400 parts of mixed solvent. Nitrogen gas is introduced, and 100 parts of the macromolecular initiator obtained in Step 11, 3.5 parts of cuprous bromide CuBr, and 7 parts of pentamethyldiethylenetriamine are added. The temperature is raised to 87°C and reacted for 7 hours. After the reaction is completed, the solvent is removed to obtain the copolymer. The mixed solvent is acetone / toluene in a volume ratio of 4:1. Step 13: Add all the copolymer obtained in step 12 to 1000 mL of 0.1 mol / L silver nitrate solution, heat to 35°C and stir for 11 min, then add 250 mL of 0.1 mol / L sodium borohydride solution and continue stirring for 1.5 h. After the reaction is complete, separate the solvent and dry to obtain polysiloxane-b-sulfonic acid carboxylic acid complexed silver segments, i.e., antibacterial agent A.

[0044] Preparation Example 2 The only difference between Preparation Example 2 and Preparation Example 1 is that in step 12, 2-acrylamide-2-methylpropanesulfonic acid is completely replaced by an equal amount of acrylic acid, that is, the polymerization is carried out using only acrylic acid as a monomer to obtain antibacterial agent B.

[0045] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that in step 12, all acrylic acid is replaced by an equal amount of 2-acrylamide-2-methylpropanesulfonic acid, that is, the polymerization is carried out using only 2-acrylamide-2-methylpropanesulfonic acid as a monomer to obtain antibacterial agent C.

[0046] Preparation Example 4 Preparation of styrene-b-quaternary ammonium salt segment-b-long chain hydrophobic polyolefin copolymer Step 21: Add 50 parts of styrene to 300 parts of toluene, purge with nitrogen, add 0.5 parts of initiator, 3.5 parts of cuprous bromide CuBr, and 7 parts of pentamethyldiethylenetriamine, heat to 90℃ and react for 6-8 hours. After the reaction is complete, remove the solvent and dry to obtain polymer A. Step 22: Add 50 parts of acryloyloxyethyltrimethylammonium chloride to 500 parts of mixed solvent, purge with nitrogen, add all of the polymer A obtained in step 11, 3.5 parts of cuprous bromide CuBr, and 7 parts of pentamethyldiethylenetriamine, heat to 90℃ and react for 7 hours. After the reaction is completed, remove the solvent and dry to obtain polymer B. Step 23: Add 50 parts of dodecyl vinyl ether to 800 parts of mixed solvent, purge with nitrogen, add all of the polymer B obtained in step 22, 3.5 parts of cuprous bromide CuBr, and 7 parts of pentamethyldiethylenetriamine, heat to 100℃ and react for 8 hours. After the reaction is complete, remove the solvent and dry to obtain styrene-b-quaternary ammonium salt segment-b-long chain hydrophobic polyolefin copolymer, i.e., antibacterial agent D.

[0047] In steps 22 and 23, the mixed solvent is a mixture of acetone and toluene in a volume ratio of 4:1.

[0048] Preparation Example 5 The only difference between Preparation Example 5 and Preparation Example 4 is that: dodecyl vinyl ether is replaced by styrene in an equal amount to obtain styrene-b-quaternary ammonium salt segment-b-styrene copolymer, i.e., antibacterial agent E.

[0049] Preparation Example 6 The only difference between Preparation Example 6 and Preparation Example 4 is that styrene is replaced by an equal amount of dodecyl vinyl ether to obtain a long-chain hydrophobic polyolefin-b-containing quaternary ammonium salt segment-b-long-chain hydrophobic polyolefin copolymer, i.e., antibacterial agent F.

[0050] Preparation Example 7 Preparation of quaternary ammonium salt segment-β-styrene-β-long-chain hydrophobic polyolefin copolymers Step 21: Add 50 parts of acryloyloxyethyltrimethylammonium chloride to 300 parts of acetone, purge with nitrogen, add 0.5 parts of initiator, 3.5 parts of cuprous bromide CuBr, and 7 parts of pentamethyldiethylenetriamine, heat to 90℃ and react for 6-8 hours. After the reaction is complete, remove the solvent and dry to obtain polymer A. Step 22: Add 50 parts of styrene to 500 parts of mixed solvent, purge with nitrogen, add all of the polymer A obtained in step 11, 3.5 parts of cuprous bromide CuBr, and 7 parts of pentamethyldiethylenetriamine, heat to 90℃ and react for 7 hours. After the reaction is complete, remove the solvent and dry to obtain polymer B. Step 23: Add 50 parts of dodecyl vinyl ether to 800 parts of mixed solvent, purge with nitrogen, add all of the polymer B obtained in step 22, 3.5 parts of cuprous bromide CuBr, and 7 parts of pentamethyldiethylenetriamine, heat to 100℃ and react for 8 hours. After the reaction is complete, remove the solvent and dry to obtain antibacterial agent G. The mixed solvent is an acetone / toluene mixture with a volume ratio of 4:1. Example

[0051] The composite processing technology for inorganic powders includes the following steps: Step 1: Add 5 parts sodium silicate to 10 times its own weight of deionized water at a temperature of 75°C, maintain the temperature in a water bath, and stir until dissolved; weigh out 5 parts sodium silicate and add it to 5 times its own weight of deionized water at a temperature of 75°C, maintain the temperature in a water bath, and stir until dissolved; slowly add aluminum sulfate solution to the stirred sodium silicate solution at a stirring speed of 1200 rpm; after the solution turns into a milky white slurry, continue stirring for 15 minutes to obtain an active slurry. Step 2: Add 100 parts of powder to the reactor, then add 10-20 times the weight of the powder in 5% ethanol aqueous solution and reflux and stir to form a slurry. The reactor temperature is 75℃ and the stirring speed is 1200rpm. Step 3: Add the active slurry from Step 1 to the continuously stirred slurry from Step 2, and stir for 40 minutes to obtain a mixed slurry. The stirring speed is 1800 rpm. Step 4: The mixed slurry is filtered by pressure and washed with water until the conductivity is ≤150μS / cm. The water washing is then stopped to remove water-soluble salts. The mixture is then sent to a hot air circulating oven for drying. The drying temperature is set at 85℃ for 12 hours. The temperature is then increased to 110℃ and the drying continues for 21 hours to obtain the filter cake. Step 5: Put the obtained dried filter cake into a high-speed mixer, set the mixing speed to 1250 rpm, and mix. Under the action of the high-speed mixer, the filter cake is broken into powder again and forms a vortex. Add 8 parts of silane and mix for 20 minutes. Then stop mixing. Put the mixed powder into a hot air circulating oven for drying again. Set the drying temperature to 100℃ and dry for 8 hours to allow the silane and powder to combine smoothly. Take the mixed powder out of the oven and use a hammer mill for further crushing to obtain the finished composite powder.

[0052] The powder consists of 85 parts mica and 15 parts nano zinc oxide; the silane is polydimethylsiloxane; and the molar ratio of sodium silicate to aluminum sulfate is 3.2:1. Example

[0053] The composite processing technology for inorganic powders includes the following steps: Step 1: Add 5.5 parts sodium silicate to 10 times its own weight of deionized water at a temperature of 75°C, maintain the temperature in a water bath, and stir until dissolved; weigh out sodium silicate and add it to 5 times its own weight of deionized water at a temperature of 75°C, maintain the temperature in a water bath, and stir until dissolved; slowly add aluminum sulfate solution to the stirred sodium silicate solution at a stirring speed of 1200 rpm; after the solution turns into a milky white slurry, continue stirring for 15 minutes to obtain an active slurry.

[0054] Step 2: Add 100 parts of powder to the reactor, then add 10-20 times the weight of the powder in 5% ethanol aqueous solution and reflux and stir to form a slurry. The reactor temperature is 75℃ and the stirring speed is 1200rpm. Step 3: Add the active slurry from Step 1 to the continuously stirred slurry from Step 2, and stir for 40 minutes to obtain a mixed slurry. The stirring speed is 1800 rpm. Step 4: The mixed slurry is filtered by pressure and washed with water until the conductivity is ≤150μS / cm. The water washing is then stopped to remove water-soluble salts. The mixture is then sent to a hot air circulating oven for drying. The drying temperature is set at 85℃ for 12 hours. The temperature is then increased to 110℃ and the drying continues for 21 hours to obtain the filter cake. Step 5: Put the obtained dried filter cake into a high-speed mixer, set the mixing speed to 1250 rpm, and mix. Under the action of the high-speed mixer, the filter cake is broken into powder again and forms a vortex. Add 8 parts of silane and mix for 20 minutes. Then stop mixing. Put the mixed powder into a hot air circulating oven for drying again. Set the drying temperature to 100℃ and dry for 8 hours to allow the silane and powder to combine smoothly. Take the mixed powder out of the oven and use a hammer mill for further crushing to obtain the finished composite powder.

[0055] The powder in 100 parts consisted of: synthetic mica; polydimethylsiloxane; and sodium silicate and aluminum sulfate in a molar ratio of 3.2:1.

[0056] Examples 1 and 2 respectively demonstrated the adhesion and lamination of different powders and the same powder. Figure 1 and Figure 2 All images are electron microscope (EM) images of the composite powder obtained in step 4 after filter cake crushing, i.e., composite powder without silane treatment. It can be seen that the powder particles can form good adhesion, and the powder bonding was achieved through a simple slurry mixing and drying process.

[0057] Examples 3-12 further tested the modification effects of silanes and antibacterial agents. Example

[0058] The composite processing technology for inorganic powders includes the following steps: Step 1: Add 5 parts sodium silicate to 10 times its own weight of deionized water at a temperature of 75°C, maintain the temperature in a water bath, and stir until dissolved; weigh out 5 parts sodium silicate and add it to 5 times its own weight of deionized water at a temperature of 75°C, maintain the temperature in a water bath, and stir until dissolved; slowly add aluminum sulfate solution to the stirred sodium silicate solution at a stirring speed of 1200 rpm; after the solution turns into a milky white slurry, continue stirring for 15 minutes to obtain an active slurry.

[0059] Step 2: Add 100 parts of powder to the reactor, then add 10-20 times the weight of the powder in 5% ethanol aqueous solution and reflux and stir to form a slurry. The reactor temperature is 75℃ and the stirring speed is 1200rpm. Step 3: Add the active slurry from Step 1 to the continuously stirred slurry from Step 2, and stir for 40 minutes to obtain a mixed slurry. The stirring speed is 1800 rpm. Step 4: The mixed slurry is filtered by pressure and washed with water until the conductivity is ≤150μS / cm. The water washing is then stopped to remove water-soluble salts. The mixture is then sent to a hot air circulating oven for drying. The drying temperature is set at 85℃ for 12 hours. The temperature is then increased to 110℃ and the drying continues for 21 hours to obtain the filter cake. Step 5: Put the obtained dried filter cake into a high-speed mixer, set the mixing speed to 1250 rpm, and mix. Under the action of the high-speed mixer, the filter cake is broken into powder again and forms a vortex. Add 8 parts of silane and 3 parts of antibacterial agent, mix for 20 minutes, and then stop mixing. Put the mixed powder into a hot air circulating oven for drying again. Set the drying temperature to 100℃ and dry for 8 hours to allow the silane and powder to combine smoothly. Take the mixed powder out of the oven and use a hammer mill for further crushing to obtain the finished composite powder.

[0060] The 100 parts of powder consisted of: 85 parts mica and 15 parts nano zinc oxide; the silane was polydimethylsiloxane; the molar ratio of sodium silicate to aluminum sulfate was 3.2:1; and the antibacterial agent was the antibacterial agent A of Preparation Example 1 and the antibacterial agent D of Preparation Example 4 in a mass ratio of 5:1.

[0061] Example 4-12 The composite processes in Examples 4-12 are basically the same as those in Example 3, differing only in the choice of antibacterial agent. Specifically, in Example 4, the antibacterial agent is antibacterial agent A from Preparation Example 1 and antibacterial agent D from Preparation Example 4 in a mass ratio of 2:1; in Example 5, the antibacterial agent is antibacterial agent A from Preparation Example 1 and antibacterial agent D from Preparation Example 4 in a mass ratio of 7:1; in Example 6, the antibacterial agent is antibacterial agent D from Preparation Example 4; in Example 7, the antibacterial agent is antibacterial agent A from Preparation Example 1; and in Example 8, the antibacterial agent is antibacterial agent B from Preparation Example 2 and antibacterial agent D from Preparation Example 4 in a mass ratio of 5:1. 1; In Example 9, the antibacterial agent was prepared by antibacterial agent C of Example 3 and antibacterial agent D of Example 4 in a mass ratio of 5:1; In Example 10, the antibacterial agent was prepared by antibacterial agent A of Example 1 and antibacterial agent E of Example 5 in a mass ratio of 5:1; In Example 11, the antibacterial agent was prepared by antibacterial agent A of Example 1 and antibacterial agent F of Example 6 in a mass ratio of 5:1; In Example 12, the antibacterial agent was prepared by antibacterial agent A of Example 1 and antibacterial agent G of Example 7 in a mass ratio of 5:1.

[0062] It should be noted that when two antibacterial agents are used together in Examples 3-12, the two antibacterial agents can be mixed and added together, and the total amount of antibacterial agents remains unchanged.

[0063] Antibacterial test: The composite powders obtained in the embodiments and comparative examples of this application were subjected to antibacterial tests. Referring to the Test Method for Antibacterial Properties of Nano-Inorganic Materials (GB / T 21510-2008)-A, the antibacterial rate I of the standard bacterial strains *Escherichia coli* 8099 and *Staphylococcus aureus* ATCC6538 was tested. The composite powder samples obtained in the embodiments and comparative examples were placed at 60°C and 75% humidity for 40 days, and the antibacterial rate II was tested. The percentage decrease in antibacterial rate was calculated as (initial antibacterial rate I - antibacterial rate II) / initial antibacterial rate * 100%. The test results are shown in Table 1. Table 1 Antibacterial rate 1% Antibacterial rate decreased by %. Antibacterial rate 1% Antibacterial rate decreased by %. strains E. coli E. coli Staphylococcus aureus Staphylococcus aureus Example 1 76.7 20.6 81.1 19.8 Example 3 99.9 0.3 99.4 0.4 Example 4 99.0 1.2 98.6 1.5 Example 5 99.3 0.8 98.7 1.0 Example 6 93.5 6.3 92.6 7.1 Example 7 95.2 5.9 93.5 6.2 Example 8 98.3 1.8 97.6 2.0 Example 9 93.0 7.4 91.4 8.5 Example 10 98.6 1.6 97.9 1.7 Example 11 98.3 1.4 97.5 1.7 Example 12 99.5 0.6 99.0 0.7 As can be seen from Examples 1 and 3-12, after surface antibacterial treatment of the composite powder, the antibacterial rate against Escherichia coli and Staphylococcus aureus both reached over 93%, maintaining high antibacterial activity for a prolonged period under high temperature and humidity for 40 days. Examples 3-7 show that the combined use of polysiloxane-b-sulfonic acid carboxylic acid complex silver segments and styrene-b-quaternary ammonium salt segments-b-long-chain hydrophobic polyolefin copolymer as an antibacterial agent significantly improves its antibacterial properties and antibacterial durability compared to using either one alone, and adjusting their ratio can achieve even better antibacterial effects.

[0064] As can be seen from Examples 3 and 8-9, the copolymerization of polysiloxane-b-sulfonic acid carboxylic acid complex silver segments through the participation of sulfonic acid monomers and carboxylic acid monomers is beneficial for optimizing antibacterial properties. As can be seen from Examples 3 and 10-12, the triblock structure of styrene-b-quaternary ammonium salt segment-b-long-chain hydrophobic polyolefin copolymer is more conducive to its synergistic effect with polysiloxane-b-sulfonic acid carboxylic acid complex silver segments, thereby further enhancing antibacterial properties.

[0065] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A composite processing technology for inorganic powders, characterized in that, The composite treatment process includes: Step 1: Sodium silicate is added to deionized water at a constant temperature of 60-90℃ and stirred to dissolve to obtain a sodium silicate solution; aluminum sulfate is added to deionized water at a constant temperature of 60-90℃ and stirred to dissolve to obtain an aluminum sulfate solution; the aluminum sulfate solution is slowly added to the sodium silicate solution and stirred until the solution becomes a milky white slurry, and stirring is continued for 10-20 minutes to obtain an active slurry; Step 2: Add the powder to the reactor, then add an ethanol aqueous solution and stir to form a slurry. The reactor temperature is 60-90℃. Step 3: Add the active slurry from Step 1 to the slurry from Step 2 and stir for 30-50 minutes to obtain a mixed slurry; Step 4: Press and filter the mixed slurry, wash it with water, dry it at 80-90℃, and then heat it to 105-120℃ to dry it again to obtain filter cake; Step 5: The filter cake is fed into a high-speed mixer, silane is added, the mixture is mixed, and then dried and crushed again to obtain composite powder.

2. The composite processing technology for inorganic powders according to claim 1, characterized in that, The molar ratio of sodium silicate to aluminum sulfate is (3.1-3.3):

1.

3. The composite processing technology for inorganic powders according to claim 1, characterized in that, The powder in step 2 contains at least one of the following: synthetic fluorophlogopite, mica, sericite, talc, silica, sodium calcium aluminum silicate, titanium dioxide, iron oxide, pearl powder, calcium carbonate, boron nitride, zinc oxide, aluminum hydroxide, aluminum oxide, lauroyl lysine, and ceramide NP.

4. The composite processing technology for inorganic powders according to claim 1, characterized in that, In step 5, the silane is at least one of triethoxyoctylsilane and polydimethylsiloxane.

5. The composite processing technology for inorganic powders according to claim 1, characterized in that, The mass ratio of the powder to silane is 100:(1-10).

6. The composite processing technology for inorganic powders according to claim 1, characterized in that, In step 5, an antibacterial agent is added simultaneously with silane; the antibacterial agent is a polysiloxane-b-silver segment containing sulfonic acid carboxylic acid complex and a styrene-b-quaternary ammonium salt segment-b-long chain hydrophobic polyolefin copolymer.

7. The composite processing technology for inorganic powders according to claim 6, characterized in that, The mass ratio of the polysiloxane-b-containing sulfonic acid carboxylic acid complexed silver segment and the styrene-b-containing quaternary ammonium salt segment-b-long chain hydrophobic polyolefin copolymer is 4-6:

1.

8. The composite processing technology for inorganic powders according to claim 6, characterized in that, The preparation process of the polysiloxane-b-sulfonic acid carboxylic acid complex silver segment includes: brominizing amino polysiloxane to obtain a macromolecular initiator, then initiating the polymerization of 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid through the macromolecular initiator to obtain a graft copolymer, adding the copolymer to a silver ion solution for complexation, and reducing the product in situ with a reducing agent.

9. The composite processing technology for inorganic powders according to claim 6, characterized in that, The preparation process of the styrene-b-quaternary ammonium salt segment-b-long chain hydrophobic polyolefin copolymer includes: stepwise initiation of polymerization of monomers styrene, acryloyloxyethyltrimethylammonium chloride and dodecyl vinyl ether monomers by ATRP initiator to obtain a terpolymer.

10. A composite powder, characterized in that, It is prepared by the composite processing technology of the inorganic powder described in any one of claims 1-9.

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